Re: Heat crazed mad scientist

["Bruce Plecan" <nacelp@bright.net>]

> In order to quantify the flow increase, and thus the talk of laminar vs
> turbulent flow, a velocity must be calculated from the area, and cfm flow
> of the engine at different speeds.  Once the velocity and reynolds number
> is calcuated, then you can see whether or not turbulent or laminar flow is
> present.

What makes this all fall apart is there is no specific velocity in a intake
tract.  The airflow is in pulses.

 Either way, in a stock TPI throttle body, there is a abrupt edge
> where the airfoil goes.  Any time there is an abrupt change in direction,
> flow separation will occur, and it will occur easier at higher velocities.
> Flow separation can be avoided or lessened by smoothing out the abrupt
> changes in the device you are flowing air in, be it a manifold head port,
> or a throttle body.  The airfoils'

Using the word airfoil really is a stretch

 job is to fill in a dead spot between
> the two openings, thus making the change in direction less abrupt.  This
> should increase the flow due to the smaller amount of flow separation from
> the side of the walls.

So, then using about the same logic here, running with the tailgate open on
a pickup should inhance mileage, right?.  Trouble is it don't work that way
(most often).  The air "bubble" formed behind the cab turns out to smooth
the air flow behind the cab and over the gate then all the turbulence of
having it open and reducing the size of the "bubble".

 NASCAR guys do this to the inside of the intake,
> trying to fill in dead spots in flow that could cause flow separation,
> vortices, and reversion, all which adversly effect flow rates.

Which matches what I said.

 I do have
> to disagree with grumpy on the fusalage being the same as the intake.

Hang in there you'll get it right eventually.

> Inner flow and outer flow can differ significantly when boundaries and
> finite areas are considered, plus everything on a plane is designed for
> lift and minimal drag....

Heard that stuff before, trouble is the engines don't read the same
material.

Just in what you've said, one might be tempted to think the airfoils would
have to work wonders, OK, why don't the performance numbers reflect that?.
I'd suggest reading some of Smokey Yunicks old stuff.


> Subject:  RE: Heat crazed mad scientist
> I don't have anything intelligent to add to this topic, but I find it
> interesting that ALL (?) the aftermarket, high-flow, twin-blade throttle
> bodies basically have the airfoil piece designed in the housing.  Do they
> do
> it for looks or just for show?

90% of the trick of the week stuff is just for show.  Hell if it ain't
pretty no one will buy it.  We spent hours polishing ports, so the customer
would be happy.  Even told them they were losing a few HP that way.  Only
maybe 1 in 10 guys would perfer the "rough cut".
Grumpy
>

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